Review Article: The Existing Models for Simulation of Pulsed and Reciprocating Columns—How Well do they Work in the Real World?

Abstract

The purpose of this article is to review the state of art of the existing approaches to the design and analysis of pulsed and reciprocating columns, compare the merits of the theoretical models vs. the experimental “black box” method, and try to recommend a way to obtain a fruitful cooperation between researchers using different approaches. There are three main theoretical approaches: models based on the correlation of single parameters (holdup, drop size, mass‐transfer coefficient etc.), drop population balances, and computational fluid dynamics (CFD). At present, the design of new columns is based only on experimental data from piloting, sometimes with the assistance of mass‐balance simulators. And the experimental “black box approach” has proven to be efficient and quick, especially since at present no company considers the erection of a new column without some experimental verification. In the long term powerful models may enable the solution of many solvent extraction problems with reliability that does not require experimental verification. In order to be widely useful, these models have to be transformed into user‐friendly simulators that require only easily available data as input. To achieve this, there must be close cooperation between the academic world and industry. Otherwise, they will simply remain academic exercises. And at the present state of knowledge, pilot‐plant testing remains an almost inevitable preliminary step to a full‐scale column design.

Keywords:

• Hydrodynamics
• pulse disk and doughnut column
• pulse sieve‐plate column
• Karr column
• modeling
• simulation
• process development
• holdup
• mass‐transfer

Acknowledgment

The author wishes to thank Mr. Sydney Miller of Bateman Engineering for his valuable input to this article.